Experimental confirmation of whispering gallery modes with different parities in elliptical microdisks

Abstract

A phase shift of pi between two whispering gallery modes with the same angular momentum number in elliptically deformed microdisks has been demonstrated experimentally using far-field measurements. The near-field pattern of one mode has a phase shift of pi relative to that of the other mode. With the experimental techniques used in this study, we were able to excite the two modes separately. The parity of the individual mode was identified by analyzing the far-field pattern of the identical parity. The distinct far-field pattern was observed according to the parity of the mode. Finite-difference time-domain (FDTD) calculations were found to be in good agreement with the experimental results.